The head of the ITV company Carlton Communications is threatening to call off the planned merger with Granada if the companies are forced to sell their advertising sales houses as part of the deal.

Michael Green told the Observer newspaper that spinning off the advertising houses would be too high a price.

"It would not make commercial sense; what would be the point of being divorced from our principal income stream?" he asked.

Last week the Competition Commission suggested that both Carlton and Granada might have to sell their advertising houses to allow a deal to go ahead.

Can you image Rupert Murdoch at Sky agreeing to lose control of his advertising - it's unthinkable

Michael Green, Carlton boss

"ITV is already dysfunctional in that we are a single programming entity but made up of different companies," Mr Green said in an interview with the newspaper.

"This merger is about creating a single, major ITV grouping, one that can take on the competition.

"Why make it more dysfunctional?

"Can you image Rupert Murdoch at Sky agreeing to lose control of his advertising - it's unthinkable."

Most analysts had been expecting the commission to insist on the sale of only one of the advertising sales houses.

Although the commission has written to the two independent television companies setting out issues and remedies for them to consider - including the question of the advertising sales houses - it has not yet made a decision.

It could decide that the merger is against the public interest and block the deal completely.